1. Field of the Invention
The present invention relates to a printing system in which the type of a printing medium (printing paper) is automatically detected, and a printing mode suitable for the detected printing medium type is automatically selected.
2. Description of the Related Art
In general, a printing system includes a printer such as a color printer, a host computer for generating print data and controlling the printer, and a communication interface for connecting the printer and the host computer with each other.
Among a large number of types of color printers, an ink-jet printer is used to print on a wide variety of printing media. Some examples of printing medium types are plain paper widely used by copying machines, paper coated with silica or the like to suppress ink bleeding and to achieve good coloring, glossy paper used to print a photographic quality image similar to an image achieved by silver salt photography, a transparency film, transfer paper for iron printing, and a back print film.
When printing on a medium is performed, a user selects a printing medium type in setting of a printer driver so that printing is properly performed depending on the printing medium type.
Recently, a printer having a sensor for automatically detecting a printing medium type has been proposed. Such a sensor is called a medium sensor. In this type of printer, a given printing medium is categorized into one of four or five types as shown in FIG. 8. In the example shown in FIG. 8, a printing medium is illuminated with light, and the type of the printing medium is determined on the basis of reflected light (regular reflected light and diffuse reflected light).
However, the conventional technique has the following problems.
In the case in which ink-jet printers do not have a medium sensor, users have to specify a medium type before starting a printing operation. However, selecting a correct medium type from a large number of medium types is troublesome to users. In some cases, selection is incorrectly performed against the intention of a user. When a user does not have sufficient knowledge about printing media, the user cannot properly set the printing conditions depending on the medium type. In particular, when a printing medium is used which is not included in the list of selectable printing media prepared by default by a manufacturer of a printer, it is required to determine which one of printing medium type in the list is most similar to the printing medium which is going to be used. To make the determination, a user has to do a troublesome job including a test printing which needs a long time and which often results in wasting expensive printing media and ink.
To avoid some of the problems described above, it has been proposed to provide a medium sensor on a printer so that a printing medium type is automatically detected and a printing mode most suitable for a printing medium is automatically determined. However, even such a type of printer has still problems as described below.
Printing medium types that can be detected by such a type of printer having a medium sensor are limited to particular medium types such as those shown in FIG. 8. Although the automatic detection of printing medium types does not generally results in great deviations from the best printing conditions, it is still difficult to precisely set printing conditions to be most suitable for a given printing medium. The difficulty results from variations in characteristics of the sensor, variations in characteristics of the same type of printing medium from one medium to another, and the presence of a very large number of printing medium types which are commercially available and which should be correctly detected by the medium sensor. If it is tried to simply increase the number of printing medium types in the automatic detection, the result is an increase in probability that an incorrect medium type is selected. When a printing medium of a type other than those recommended by a manufacturer of the printer, a most similar medium type is automatically selected, and high precision adjustment is impossible.